Is black seed oil safe during pregnancy?

What does the evidence say about black seed oil during pregnancy?

1. Black seed has traditionally been used as an emmenagogue, a substance used to bring on menstrual flow, among its other folk-medicine uses. 1
2. In animal research, extracts from black seed inhibited the uterus's contraction response to oxytocin, and a hexane extract of the seeds stopped pregnancy from continuing in rats at a dose of 2 grams per kilogram daily. 1
3. In a human clinical trial, black seed oil was given specifically to help the body complete a pregnancy loss already confirmed by ultrasound, not as a supplement during an ongoing, wanted pregnancy, which points to real, measurable effects on the uterus. 2
4. Limited information indicates black seed is generally well tolerated, though it can cause allergic contact dermatitis, and no data exist on whether its components pass into breastmilk or on its safety for infants. 3
5. Separately, general safety reviews describe black cumin as well tolerated with only mild, transient side effects like stomach upset and headache, and no reports of liver injury, but this safety information does not address pregnancy or reproductive use. 4

Is black seed oil safe in each trimester?

• First trimester. Any documented uterine and reproductive activity from black seed matters most in the first trimester, when implantation and early development are underway, and it's also the stage least studied in humans.
• Second trimester. There's no dedicated human research on black seed oil at any stage of pregnancy, so the lack of second-trimester-specific data isn't reassuring, it just reflects how little has been studied overall.
• Third trimester. Traditional use of black seed to bring on menstrual flow, along with its documented effects on uterine muscle response, are reasons to stay cautious through the third trimester rather than starting it close to delivery.